1. Field of the Invention
The present invention relates to a display apparatus, and more specifically to a Liquid Crystal Display (LCD) apparatus having main gate drivers for driving main pixels and sub-gate drivers for driving sub-pixels.
2. Discussion of the Background
In general, an LCD apparatus may include an LCD panel including a bottom substrate, a top substrate facing the bottom substrate and a liquid crystal layer interposed between the bottom substrate and the top substrate. The LCD panel may also include gate lines, data lines and pixels connected to the gate lines and the data lines. Signals are supplied to the gate lines and data lines to apply an electric field across the liquid crystal layer. Since the liquid crystals in the liquid crystal layer may have an anisotropic dielectric constant, the alignment of the liquid crystals may change when the electric field is applied across the liquid crystal layer. In addition, since the liquid crystals have an anisotropic refractive index, light transmittance of the LCD apparatus may vary according to the alignment of the liquid crystals. The LCD apparatus applies an electric field between the two substrates such that the liquid crystals have a light transmittance corresponding to display information transmitted as data signals. Thus, the alignment of the liquid crystals may vary according to the applied electric field.
Further, the alignment of the liquid crystals may control the transmission of backlight illumination through the liquid crystal layer to display images on the LCD apparatus.
The LCD apparatus may include a gate driver for sequentially outputting a gate pulse to the gate lines and a data driver for outputting a data voltage to the data lines. The gate driver and the data driver may each be arranged as a chip on a film of the LCD panel.
Recently, in order to reduce the number of chips, an LCD apparatus may employ a gate-IC-less (GIL) structure in which the gate driver is arranged directly on the bottom substrate by a thin film forming process. In the LCD apparatus with the GIL structure, the gate driver may include a shift register having multiple stages connected in series to provide gate pulses to the gate lines.
In addition, patterned vertical alignment (PVA) mode LCD apparatuses, multi-domain vertical alignment (MVA) mode LCD apparatuses, and super-patterned vertical alignment (S-PVA) mode LCD apparatuses have been developed in order to improve the viewing angle of LCD apparatuses.
For example, an S-PVA mode LCD apparatus may have a pixel including two sub-pixels, in which each sub-pixel has a main pixel electrode and a sub-pixel electrode and different sub-voltages are applied to the main pixel electrode and the sub-pixel electrode in order to form domains having different grays. Since an observer viewing an image displayed on the LCD apparatus may recognize an intermediate value between the main voltage and the different sub-voltage, the lateral viewing angle of the LCD apparatus may not be narrowed by the distortion of a gamma curve at the intermediate gray level, so that the lateral visibility of the LCD apparatus may be improved.
The S-PVA mode LCD apparatuses may be classified as a coupling capacitor (CC) type LCD apparatus or a two transistor (TT) type LCD apparatus according to the driving scheme thereof.
A CC type LCD apparatus may further include a coupling capacitor between the main pixel electrode and the sub-pixel electrode. The main voltage applied to the main pixel electrode may be modified by a stored voltage in the capacitor. Therefore, the main voltage applied to the main pixel electrode may be different from the sub-voltage applied to the sub-pixel electrode.
A TT type LCD apparatus may employ two transistors that are turned on sequentially with a predetermined time interval to apply main voltages to the main electrodes and sub-pixel voltages to the sub-pixel electrodes, where the main voltages and the sub-pixel voltages have different voltage levels. However, the driving frequency for the TT type LCD apparatus may be increased in order to drive the two transistors. The increase in driving frequency may increase the power consumption of the TT type LCD apparatus.
Further, in the TT type S-PVA mode LCD apparatus having the GIL structure, the number of stages of the gate driver may increase since twice the number of transistors may be driven. The additional stages in the gate driver may increase the size of the LCD panel, which also may increase power consumption of the LCD apparatus.